More work on Market functionality and UI

* Now loads all market items.
* Can filter market items.
* Will load market offers on items.
* Edited some UI images.

modules/gamelib/thing.lua

@@ -0,0 +1,48 @@
+ThingCategoryItem = 0
+ThingCategoryCreature = 1
+ThingCategoryEffect = 2
+ThingCategoryMissile = 3
+ThingInvalidCategory = 4
+ThingLastCategory = ThingInvalidCategory
+
+ThingAttrGround           = 0
+ThingAttrGroundBorder     = 1
+ThingAttrOnBottom         = 2
+ThingAttrOnTop            = 3
+ThingAttrContainer        = 4
+ThingAttrStackable        = 5
+ThingAttrForceUse         = 6
+ThingAttrMultiUse         = 7
+ThingAttrWritable         = 8
+ThingAttrWritableOnce     = 9
+ThingAttrFluidContainer   = 10
+ThingAttrSplash           = 11
+ThingAttrNotWalkable      = 12
+ThingAttrNotMoveable      = 13
+ThingAttrBlockProjectile  = 14
+ThingAttrNotPathable      = 15
+ThingAttrPickupable       = 16
+ThingAttrHangable         = 17
+ThingAttrHookSouth        = 18
+ThingAttrHookEast         = 19
+ThingAttrRotateable       = 20
+ThingAttrLight            = 21
+ThingAttrDontHide         = 22
+ThingAttrTranslucent      = 23
+ThingAttrDisplacement     = 24
+ThingAttrElevation        = 25
+ThingAttrLyingCorpse      = 26
+ThingAttrAnimateAlways    = 27
+ThingAttrMinimapColor     = 28
+ThingAttrLensHelp         = 29
+ThingAttrFullGround       = 30
+ThingAttrLook             = 31
+ThingAttrCloth            = 32
+ThingAttrMarket           = 33
+ThingAttrChargeable       = 254 -- deprecated
+ThingLastAttr             = 255
+
+SpriteMaskRed = 1
+SpriteMaskGreen = 2
+SpriteMaskBlue = 3
+SpriteMaskYellow = 4